Dynamo-electric machine



Jan. 11 1927. 1,613,625

' A H. M. STOLLER DYNAMO ELECTRIC MACHINE Filed Dec 30, 1922 F/y/ Z5 7 26 //7 l/eflfor."

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Patented Jan. 11, 1927.

UNITED STATES PATENT OFFICE.

HUGH M. STOLLER, OF MOUNTAIN LAKES, NEVI JERE Y. ASSIGNOR TO WESTERN ELEC- TRIO COMPANY, INCORPORATED, OF NEW YORK, ll. 1., A CORPORATION OF NEVJ YORK.

DYNAMO-ELECTRIO MIACEINE.

Application filed December 30. 1922.

This invention relates to dynamo electric machines and its object in general is to improve the construction and operation of the dynamo electric machines of the synchro nous type.

A feature of this invention has to do with the structure whereby there is produced a simple, cheap and commercial term of convertcr operable from a standard voltage single phase source to deliver a direct current of small value suitable for operating vacuum tube apparatus, electric phonograph reproducers and the like. In accordance with this feature of the invention a single phase series wound commutator motor of standard design and construction is operated at synchronous speed and is provided with a generator commutator. The field poles are provided with secondary windings which form a source of alternating current suitable for energizing the filaments of thermionic tubes.

Referring to the drawing: Fig. 1 is a fragmentary cross-sectional view, partially in elevation, showing the mechanical construe tion of this invention; Fig. 2 is an elevation looking from the left of Fig. 1; Fig. 3 is a cross-sectional view taken on the line 33 of Fig. 1; and Fig. 4 is a schematic diagram showing the connections of the armature winding with the motor and generator commutators, the views of both conimutators being taken from opposite ends of Fig. 1 as indicated by the arrows desigmating the direction of rotation.

The machine comprises bi-polar field structure 1, armature 2, drum winding 3, commutator 4, brushes 5 and (S, and field exciting windings 7 and 8 arranged in the usual manner 01 a single phase series wound commutator motor. Keyed to shaft 9 there may be a magnetic member 10 comprising a salient poles 11 and 12 arranged to be influenced by field poles 13 and 14. As a comut-ator motor, armature 2 would in general rotate at an asynchronous speed but salient poles 11 and 12 are synchronously attracted by field poles 13 and l t thus causing the rotor to pull into synchronisni and operate as a synchronous motor. Poles 11 and 12 are provided with closed windings 113 and 114: respectively, of low resistance which tend to keep constant the flux through member 10, as is Well understood in the art. This Serial No. 616,037.

increases the synchronizing force and improves the operation of the machine. Unwound polar projections 15 and 16, placed midway between the main field poles 13 and 1 1. serve to decrease the reluctance of the magnetic path followed by the flux of member 10, when member 10 is at a large angle to the axis of the main field poles.

As shown schematically in Fig 4-, winding and commutator 4E comprise an ordinary drum motor winding and commutator. (Shown as a Gramme ring winding for clearness.) Field poles 13 and 1a are excited by a, single phase current and hence the instantaneous flux (p, through the field of the machine is given by Where I is the maximum field flux and *Qnr times the frequency of the source. The flux enclosed by a particular armature coil will not be the total field fiux but will be a certain proportion of it, depending upon the angle at which the coil is located at any instant. Taking the position at which the coil encloses the maximum flux as an origin, the flux enclosed within the coil. at any other position will be the total flux times the cosine of the angle between the origin and the position of the coil. Since the armature is revolving synchronously, this angle will be M, and therefore the flux (p enclosed by an ai'n'iature coil at any instant is:

It is seen that the voltage generated in w nding 3, as a result of its rotation at a velocity it, has a frequency equal to twice hence rotates at the same physical sgeed as the armature winduie'. in order that the 'elaiivc electrical speed of rotation between commutator 2t) and generator brushes and may be 2a or twice its physical speed of rotation, the diametrically opposite segments of commutator it) are cr connected as shown. The consecutive segments which occupy a semicircumference t commutator 20 are. connected by leads 23 to alternate segments oi? commutator which has the same total number of segments as commutator 20. it is seen from Fig l that with this arrangement the connecting leads are placed over only a semicircum'lerence of commutator 20 but are equally spaced over the entire circumference of commutator 4. By placing generator brushes 21 and 22 spaced as shown at an angle which is half of the angular spacing of motor brushes 5 and G, the electrical angula velocity of cross-connected commutator relative to brushes 21 and 22 is equal to 2m which is twice the angular velocity of winding 3; and hence direct current may be drawn from brushes 21 and 22.

With this arrangement brushes 21 and 22 will in generz'il commutate armature coils which are cutting flux and in order to limit the shortcircuit current in the coils and reduce sparking atbrushes 21 and 22, resistances 2% may be provided in the connections between commutators 20 and t. This may be accomplished by making the connecting leads 01 wire of resistance material, such as German silver.

Field poles l3 and 14: are traversed by a filllllt fllf'l illy var -Jing tlux which will induce an alternating Iii. M. F. in secondary windings 2.7- and 2b. These windings are duplicates ot' such a number of turns that. when connected in series, they term a suitable source of current for energizingthe filaments of thermionic tubes. Dupli ate variable re sistanceelements and 31 may be pro 'ided so tl at the lila'ment current can be adjusted without causing the average filam nt potential to Vary from the potential of point 32. The direct current yolta 'e of brushes 21 and n. a h i 421:: st

itable for applying to the plate circuit ot a therminoic tube, which may be connected as shown. any plate circuit apparatus used in conjunction with the tube being; ronlittittl between terminals $12, and I r alicnt pole member It) makes possible certain advantageous operating charach istics, For example, it may be a permanent magnet in which c: se the machine will always pull in synrhronism so that the same generator brush is positive. l'lowevcr, it is tound that member 10 and unwound polar projections 15 and lti are not essential an? tl e cost of the machine may be decreased by their omission. ll. omitted the machine is pulled into and maintained in synchronism by the interaction of the single phase lield tlur; and the current; drawn l'rom the noncrator armature.

bi-pola' machine has been illustrated c is apparent that a machine having an suit-a )le number o't' poles may be constructed in accordance with this invention. In the general case of an a pole marhine. leads t'rom the generator commutator semneuts which occupy a emi-circumterem"2 are dis tributcd over the entire armature windinc as shown in Fig. 1-. However, the cross-connection of the gene 'ator commutator is made so that segments which are spaced by an angle of are connected, and the generabetween them is equal to hat is claimed is: A. synchronous converter, comprising an ari'nature winding; electro-mag'netic field poles adjacent said winding, a generator comn'iutator connected to said winding, and a motor commutator having" a segment connected to each of the segments of said new orator commutator by leads having a substantial resistance,

2. A dynamo electric machine comprising armature, a distributed winding upon said armature, electromagnetic field poles in juxtaposition to said armature; a motor commutator connected to said winding. a {l'enerator comimitator, and means for connecting consecutive segments ot said ecu-- crater commutator which together occupy l tnitiilly halt ot' the peripheiw ol' the yannutator to points dirtributcd over the entire winding.

3. i dynammelcctric machine, roinpri -iu r an armature, a distributed winding: upon said armature; electromagnetic pics in juxta iosition to said armature; a motor commutator; a generator comu'iutator: and means for connecting consecutive segments of said generator commutator. which together occupy substantially half of the periphery oi. the generator commutator. to points tllt 'liil flllied over the entire winding.

tit)

-l, A. tlynanio-elcctric machine; comprisinn an armature, a distributed winding upon said arn'iature, n. poles in juxtaposition to said armature, a motor commutator; a genorator connnutator, means for connecting consecutive segments of said generator cominutator which together occupy substantially halt ot the periphery of said generator commutator to points distributed over the entire winding, and a pair of brushes cooperating with said generator coinn'iutator, said brush- 7T es being spaced at an angle of 5. A dynamo-electricmachine, comprising an armature, a distributed winding upon said armature, a poles in juxtaposition to said armature, a motor commutator; a gem orator commutator, means for connecting consecutive segments of said generator commutator which together occupy substantially halt ot the periphery of the gei'ierator commutator to points distributed over the entire winding, and means for electrically connectgenerator commutator segments which spaced on said generator commutator at 6. A dynamo-electric machine comprising an armature, a distributed winding upon said armature, n poles in juxtaposition to said armature, a motor commutator connected to said winding, a generator conm'mtator, and means for connecting consecutive segments of said generator commutator which together occupy substantially half of the periphery of said commutator to points distributed over the entire winding, and means for electrically connecting generator segments which are spaced at an angle of ing are an angle of substantially substantially In witness whereof, I hereunto subscribe my name this 29th day 0t December, A. D., 1922.

HUGH M. t'STOLLEl-i. 

